106 lines
2.2 KiB
C
106 lines
2.2 KiB
C
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//+-------------------------------------------------------------------------
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//
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// Copyright (C) 1992, Microsoft Corporation.
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//
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// File: fcbsup.h
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//
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// Contents: Declarations for DFS_FCB lookup support functions.
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//
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// History: 20 Feb 1993 Alanw Created
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//
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//--------------------------------------------------------------------------
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#ifndef __FCBSUP_H__
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#define __FCBSUP_H__
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//
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// In order to avoid modifying file objects which are passed
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// through the DFS and used by other file systems, DFS_FCB records
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// used by DFS are not directly attached to the file object
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// through one of the fscontext fields, they are instead
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// associated with the file object, and looked up as needed.
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//
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// A hashing mechanism is used for the lookup. Since the
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// file object being looked up is just a pointer, the hash
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// function is just a simple combination of a few of the low-
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// order bits of the pointer's address.
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//
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//
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// Declaration of the hash table. The hash table can be variably
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// sized, with the hash table size being a parameter of the hash
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// function.
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//
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typedef struct _FCB_HASH_TABLE {
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//
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// The type and size of this record (must be DSFS_NTC_FCB_HASH)
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//
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NODE_TYPE_CODE NodeTypeCode;
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NODE_BYTE_SIZE NodeByteSize;
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//
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// Mask value for the hash function. The hash table size is
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// assumed to be a power of two; the mask is the size - 1.
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//
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ULONG HashMask;
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//
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// A spinlock to protect access to the hash bucket lists.
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//
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KSPIN_LOCK HashListSpinLock;
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//
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// An array of list heads for the hash table chains. There
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// are actually N of these where N is the hash table size.
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//
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LIST_ENTRY HashBuckets[1];
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} FCB_HASH_TABLE, *PFCB_HASH_TABLE;
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NTSTATUS
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DfsInitFcbs(
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IN ULONG n
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);
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VOID
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DfsUninitFcbs(
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VOID
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);
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PDFS_FCB
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DfsLookupFcb(
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IN PFILE_OBJECT pFile
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);
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VOID
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DfsAttachFcb(
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IN PFILE_OBJECT pFileObj,
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IN PDFS_FCB pFCB
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);
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VOID
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DfsDetachFcb(
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IN PFILE_OBJECT pFileObj,
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IN PDFS_FCB pFCB
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);
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NTSTATUS
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DfsAllocateFcb(
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IN PDEVICE_OBJECT DeviceObject,
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IN PFILE_OBJECT FileObject,
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OUT PDFS_FCB *Fcb
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);
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VOID
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DfsDestroyFcb(
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IN PDFS_FCB Fcb);
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#endif // __FCBSUP_H__
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